Unmanned aerial vehicle angular reorientation

ABSTRACT

A system comprising an unmanned aerial vehicle (UAV) having wing elements and tail elements configured to roll to angularly orient the UAV by rolling so as to align a longitudinal plane of the UAV, in its late terminal phase, with a target. A method of UAV body re-orientation comprising: (a) determining by a processor a boresight angle error correction value bases on distance between a target point and a boresight point of a body-fixed frame; and (b) effecting a UAV maneuver comprising an angular role rate component translating the target point to a re-oriented target point in the body-fixed frame, to maintain the offset angle via the offset angle correction value.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of patent application Ser. No.14/947,871, filed Nov. 20, 2015, which is a continuation of patentapplication Ser. No. 14/016,602, filed Sep. 3, 2013, which is acontinuation of International Application No. PCT/US12/27619 filed Mar.2, 2012, which claims priority to and the benefit of U.S. ProvisionalApplication No. 61/448,596 filed Mar. 2, 2011, the disclosures of all ofwhich are incorporated by reference herein for all purposes.

TECHNICAL FIELD

Embodiments pertain to unmanned aerial vehicles (UAVs) and particularlyto the angular reorientation of small and/or man-portable UAVs in theendgame phase of terminal homing.

BACKGROUND

A UAV may be guided by a human-in-the-loop, a human intermittentlyup-linking course corrections, e.g., via supervisory control, or viavehicle-borne computer processing and memory store having a preloadedintercept/strike point in combination with an onboard flight pathguidance generator and outputs of inertial sensors and/or from a GlobalPositioning System (GPS) receiver.

SUMMARY

Embodiments include an unmanned aerial vehicle (UAV) that comprises aprocessor having addressable memory, the processor configured to: (a)determine a body roll angle error based on a target location in a bodyreference frame and an orientation of the UAV in the body referenceframe; and (b) determine one or more aileron actuator commands based onthe determined body roll angle error. Embodiments may also include aprocessor of the UAV further configured to bank-to-turn, and totransition to reorient in attitude based on an estimated range-to-go andan angular position of the target relative to the UAV.

Some embodiments include a method of unmanned aerial vehicle (UAV) bodyre-orientation which comprises: (a) determining, by a processor, aboresight offset angle error correction value based on a distancebetween a target point and a boresight point of a body-fixed imageframe; and (b) effecting, by the processor, an onboard control surfaceactuation maneuver comprising an angular roll component to translate thetarget point in the body-fixed frame to thereby maintain the offsetangle via the offset angle correction value. In some embodiments themethod of UAV body re-orientation may further comprise: effecting, bythe processor, an onboard control surface actuation maneuver comprisinga pitch component to translate the target point in the body-fixed frameto thereby maintain the offset angle via the offset angle correctionvalue.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and not limitation in thefigures of the accompanying drawings, and in which:

FIG. 1 depicts a top view of an exemplary embodiment of the UAV;

FIG. 2 depicts a side view of an exemplary embodiment of the UAV;

FIG. 3A depicts a top plan view of an exemplary embodiment of the UAV;

FIG. 3B depicts a side view of an exemplary embodiment of the UAV;

FIG. 4A depicts a top plan view of an exemplary embodiment of the UAV;

FIG. 4B depicts a side view of an exemplary embodiment of the UAV;

FIG. 5 depicts a tail view of an exemplary embodiment of the UAV;

FIG. 6 depicts an exemplary UAV trajectory;

FIG. 7 depicts an exemplary UAV trajectory;

FIG. 8A depicts a front end portion of the UAV rolled into an angularposition;

FIG. 8B depicts the directional warhead when projected into the plane ofthe closest approach;

FIG. 8C depicts vehicular roll around the boresight at a first time;

FIG. 8D depicts vehicular roll around the boresight at a second time;

FIG. 8E depicts a perspective of an exemplary paint ejector having anoffset angle bias from the centerline of the UAV;

FIG. 9 depicts an exemplary functional block diagram of the UAVprocessing and guidance and control subsystem;

FIG. 10 depicts, in a functional block diagram, an exemplary pitchchannel autopilot of the UAV;

FIG. 11 depicts, in a functional block diagram, an exemplary rollchannel autopilot of the UAV;

FIG. 12A depicts, in a top level flowchart, an exemplary process ofoperation; and

FIG. 12B depicts, in an exemplary flowchart, a UAV in a nominalbank-to-turn flight control operation.

DETAILED DESCRIPTION

Reference is made to the drawings that illustrate exemplary embodimentsof the UAV. FIG. 1 illustrates a top view of an exemplary embodiment ofthe UAV portion 100. The exemplary UAV is depicted as comprising afuselage 101 with a front end 110 having a homing sensor 111, e.g., apixel array for sensing visible and/or infrared light, and a deployablepayload section 112, e.g., a warhead or other payload for precisiondelivery that may be lethal or non-lethal in nature, i.e. a deployableelectronic subassembly, such as a pigmenting capsule. The front end 110may be configured to support various warheads such as those that may behigh explosive (HE), armor-piercing, a shaped-charge, anti-personnel,anti-radiation, electro-magnetic pulse (EMP) and/or a directed blast.These warheads may be removable and/or interchangeable. The front end110 may be configured to support an additional battery pack in lieu ofor in partial place of a warhead unit, which may extend the range of theUAV. Embodiments of the UAV may have a sensor suite, including one ormore forward-facing sensors 111, and one or more side-facing sensors115, that may comprise one or more of the following passive and/oractive receivers such as: a radar imaging sensor, such as a millimeterwave system; a laser receiver and/or transmitter; a laser imagingsystem, such as a light detection and ranging (LiDAR) device; and otherelectromagnetic detectors, such as radio wave receivers. Commercialsources for these exemplary front end sensors include the Micron MT9P031and 5MP CMOS Digital Image Sensor by Micron Technology, Inc. of Boise,Id. 83707-0006. The front end 110 may also include an electronicsassembly (EA) 113, or avionics, that may include a guidance processorcomprising guidance instructions that, when executed, take ininformation pertaining to the UAV position, linear and/or rotationalvelocities, linear accelerations and/or attitude, and generate commandsfor autopilot processing and/or engine control processing and/or remotehuman pilot processing. The front end 110 or particularly the EA 113 mayalso include the side-viewing sensor such as camera 115 that may bedisposed or otherwise positioned to allow viewing of an object or targetwhile the UAV is turning about the object or target. For example, bybanking the UAV such that the side-viewing sensor 115 is aimed towardthe ground, the sensor 115 could observe a ground target, or generally atarget within the UAV's plane of orbit, while the UAV revolves about thetarget. In addition to a camera, or instead of a camera, the sensor 115any of the exemplary sensors as set forth herein for the forwarddisposed or forward-facing sensor 111.

The UAV may comprise one or more power sources 114, such as batteryunits, combustion engines including internal combustions engines,turbines, or fuel cells, and power conditioning circuits. Additionally,a propulsive power source, such as a turbine engine, or a solid orliquid rocket motor, may augment or replace a propeller system.Embodiments of the UAV may include a chemical battery store, e.g.,storing approximately 44 watt-hours of energy that may be used to poweronboard electrical devices, including a propeller motor, for a flight often to thirty minutes for a UAV having an airborne, launch, or flightmass in the range of 1.0 to 1.5 kilograms, where for some UAVembodiments, and depending on propulsion system, the UAV may have alaunch mass of 0.5 to 25 kilograms. Embodiments of the UAV may besmaller and/or have shorter flight durations and/or have less mass,and/or have a different lift-to-drag ratio, and accordingly may requireless than 44-watt hours. Additional embodiments of the UAV may be largerand/or have longer flight durations, and accordingly may require morethan 44-watt hours. As the vehicle mass grows over approximately 1.3kilograms, thrust and lift requirements for an efficient terminal homingcone may require the vehicle to include a combustion engine augmenting abattery-electrical system having greater than 44-watt hours, such ahybrid system, or replace the battery-electric system with an internalcombustion engine and/or a turbine engine. The UAV may includevehicle-specific sensors, e.g., a GPS antenna and GPS receiver, as partof the EA and/or attitude and/or rate gyroscopes and/or linearaccelerometers that may be proximate to the EA and/or vehicle center ofgravity. The UAV may include a mode of thrust generation, such as apropeller 130 and a propeller motor 131. Other embodiments may use,separately or in combination, turbine motors and/or rocket motors (notshown).

The UAV may have lifting surfaces such as a starboard wing 141, a portwing 142, a port tail 144, a starboard tail 143, and one or more rudders145, 146. The wing elements 141, 142 may have actuated control surfaces147, 148, operating as elevons, or may be embodied as wings withsurfaces that may be operated, e.g., rotationally relative to thefuselage, as elevators. Embodiments of the UAV may have a minimum forlevel flight with a maneuver margin of about 1.2 to 2.0 times theacceleration of gravity, sustainable for a major portion of the durationof a sortie. In a terminal homing mode, and at intercept abort point,embodiments of the UAV may have a maneuver margin of about 2.0 to 2.5times the acceleration of gravity. Higher accelerations characterizingmaneuverability may be desired, but are balances to recognize thesehigher levels are achievable with a bigger wing, and/or higher lift,airfoils, and that those require additional weight and volume.Embodiments of the UAV may have a wing area of 0.049 square meters(about 76 square inches) and may be in the range of 0.016 square meters(about 25 square inches) to 1.0 square meters (about 1,550 squareinches).

The exemplary pair of tail elements 143, 144 may have actuated controlsurfaces, and may be operated as ailerons or elevators. The UAV mayinclude a rudder portion comprising one or more rudders where theexemplary port rudder 145 and the starboard rudder 146 of the UAV may bebody-fixed, i.e., the rudders 145, 146 function as vertical stabilizers,and accordingly, the UAV may be statically stable in yaw, i.e., intrimmed flight, the yaw center of pressure is aft of the vehicle centerof gravity thereby aerodynamically stabilizing the UAV—at least in theyaw plane. The UAV yaw stability may be augmented by articulated,controlled trailing sections or surfaces of the one or more ruddersurfaces. Some embodiments of the UAV may have a two-rudder assemblymounted on a rotatable platform conformal to the UAV fuselage to effectan augmentation in yaw control.

Accordingly, some embodiments of the UAV may be configured to transitionfrom a terminal homing mode trajectory to a target search modetrajectory and then to a terminal homing mode trajectory, where the UAVhas a launch weight mass of less than 25 kilograms, and is powered inflight via a propeller driven by a chemical battery store, a combustionengine, or both. In some embodiments, the UAV may be powered by aturbine engine. Embodiments of the UAV may be configured to transitionfrom a terminal homing mode trajectory to a target search modetrajectory and then to a terminal homing mode trajectory while havingairspeeds in the range 50 to 120 knots, and a flight duration of about20 minutes, where the exemplary UAV has a launch weight mass of 1.0 to2.0 kilograms mass, and is powered in flight via a propeller driven achemical battery store, a combustion engine, or both.

FIG. 2 shows in side view 200 the exemplary UAV where the port wing 142is shown with the trailing control surface 148 in motion and with twoantenna wires 210, 220 (not to scale) extending from the fuselage 101.One antenna element may be used as an uplink 210, particularly forreceiving a mode control signal that effects a transition from aterminal homing mode to a target search mode, or loiter mode, or atransition from target search mode to a homing mode, e.g., a terminalhoming mode. Another antennal element may be used as a downlink 220 fortransmitting data such as live video, automatic video tracking status,flight parameters, and/or UAV states, e.g., states of vehicle operationand/or flight state. A single antenna may be used for both functionswhen equipped with transceiver capability. While video data and flightstatus data may be down-linked, the UAV may process output from variousonboard flight sensors, e.g., gyros, accelerometers, GPS receiveroutputs, and target data from the image sensor 111, or other front endtarget seeker/tracker sensor, via an onboard processor to generatecontrol surface actuation commands and accordingly guide the UAV forboth target search and terminal homing phases and the transitiontherebetween. A GPS antenna 230 may be mounted conformably or within thefuselage, i.e., behind the skin of the fuselage when made of materiallargely transparent, i.e., low loss, in the GPS frequency bands.Generally, the GPS antenna may be mounted, or otherwise disposed, on oralong the UAV fuselage 101 so as to be capable of receiving signals forthe onboard GPS receiver from a GPS satellite constellation.

FIG. 3A is top plan view of the exemplary UAV where the body of the UAVis depicted as turned, in the horizontal inertial plane, a yaw angle, ψ.FIG. 3B is a side view of the exemplary UAV where the UAV is depicted asturned, i.e., an elevated bore-sight, in the local longitudinal verticalinertial plane, a pitch angle, θ. FIG. 4A is a top plan view of anexemplary embodiment of a UAV having wing elements disposed proximate toan end of the UAV. FIG. 4B is a side view of an exemplary embodiment ofa UAV having wing elements disposed proximate to an end of the UAV. FIG.5 is a tail view of the exemplary UAV where the UAV is depicted asrotated clockwise, in the local lateral vertical plane, a roll angle, φ.

FIG. 6 depicts an exemplary UAV trajectory, where the dashed horizontallines depict a direction above local ground level, and where the arcingcurve, or arcing line segments depict a direction in which the UAV ishoming toward the target at a relative time, T₁. Also depicted in FIG. 6is a crosswind that tends to push the UAV laterally off course, i.e.,away from an intercept course. The UAV may have a bank-to-turn autopilotand accordingly, may bank the UAV into the wind so as to maintain aterminal homing trajectory. FIG. 6 depicts the exemplary UAV at arelatively later time, T₂, with a bank angle into the wind. For a UAVcarrying a directed warhead, or a paint designator, and in eitherexample, a warhead that may eject matter from the UAV at an angle offsetfrom the bore-sight offset of the UAV, the resulting bank angle mayaffect targeting accuracy. Crosswind may not be the only driver for suchbanked maneuvers. The air vehicle may have on onboard side-viewingcamera where banking may provide advantage to target acquisition and/ortracking. Also, banking may be the result of the air vehicle executing acourse correction having acquired the target and initiated a terminalhoming phase or mode. The banking may also be the result of homing to amoving and/or evasive ground target, or moving and/or evasive airtarget. FIG. 6 illustrates the UAV as it transitions from a nominalflight 610 to a bank-to-turn maneuver 620 to effect anabove-ground-level trajectory toward a target while accommodating theeffects of transverse winds or other error; the crosswinds or othertranslational flight errors may be sensed at Time T₁. In this example,these errors may translate the UAV toward the left of the trajectory inthis example. A clockwise roll angle adjustment about the UAV centerlineis depicted accomplishing this maneuver by T₂. This may be embodied asan iterative process that may be repeated along the flight path.

FIG. 7 depicts an exemplary UAV trajectory where the UAV is homingtoward the target at the relative time, T₂, banking into the crosswind.The UAV may have an airspeed of 120 miles per hour (approximately 54meters per second). The roll control may be more responsive than thepitch control of the bank-to-turn UAV. So, if the relative time, T₂,represents a range-to-target of about 50 meters, the vehicle mayinitiate a roll maneuver at relative time, T₂, that may be substantiallycompleted by the relative time, T₃. The UAV, as it maneuvers to anupright orientation in this example, may translate laterally. So, in therelative time between roll maneuver completion, i.e., T₃, and warheaddetonation, or paint ejection, T₄, there may be a lateral misscomponent. E.g., a 10 mph crosswind may produce a lateral miss componentof about five to seven meters prior to warhead detonation, or paintejection. If the crosswind is estimated or measured and made availableto the UAV guidance processing, the UAV may overcompensate laterallyprior to initiating the roll maneuver so as to reduce the lateral misscomponent. The UAV may also be commanded to pitch up or pitch down tofurther aid in the aiming of the offset warhead, or paint ejector, sothat by relative time, T₄, the vehicle may have a revised pitch angle.But, the pitch maneuver may not be as responsive to changing angles asthe roll maneuver. Once the target point and boresight point aredistinguishable from one another in the camera frame, the roll channelautomatic control may be augmented to better align the boresight afterT₁, with the projected warhead vector, and so the UAV may further bank,clockwise or counterclockwise, about the nominally corrective bankingangle or instead of the nominally corrective banking angle. Once theoffset angle is aligned and a time-to-go threshold is tripped, thevehicle control system may transition into an angle control system.

FIG. 8A is a depiction of a front end portion of the UAV rolled into anangular position favoring a more accurate aiming of the offset warhead,or paint ejector. From the exemplary perspective of a boresightedbody-fixed, camera, the target will travel in an arc as the air vehiclerolls during the period of relative time T₂ to relative time T₃. Theroll presents the paint ejector at relative time T₃, in a longitudinalplane defined by the boresight axis and the forward offset angle of thepaint ejector. The range, R, is depicted in magnitude as a length to aplane orthogonal, i.e., lateral to, the boresight-offset anglelongitudinal plane; an orthogonal plane upon which may be projected theoffset angle of the offset paint ejector—depicted in magnitude as adistance, D, at relative time, T₂. For a constant offset angle andboresight angular orientation, the magnitude of the distance D decreasesas the magnitude of the range, R, decreases.

FIG. 8B depicts the directional warhead when projected into the plane ofthe closest approach, and depicts the target i.e., the boresight point.The offset angle η represents the polar distance from boresight point,i.e., the projection of the range R, to the target point in thebody-fixed camera frame. The offset angle η can be referenced in thecamera fame from the distance D from the projection of therange-to-closest-approach to the target. The distance from UAVcenterline to the direction of the warhead may be represented by d.Where the “d” may range for example from zero (i.e., at the UAVcenterline) to one-half of the diameter of the UAV, (i.e., a pointlocally tangent to the fuselage skin of the UAV.) FIG. 8B depicts theUAV at flight time T₂ FIG. 8C depicts the UAV having rolled at flighttime T₃.

FIG. 8D is a depiction, in a body-fixed camera perspective, of avehicular roll around the boresight 820, e.g., around the vehiclecenterline or roll axis of rotation, where the target 812 appears to theright of the boresight at relative time, T₂, and appears below theboresight at relative time 814, T₃. The distance from the boresight tothe target relative time, T₃, represents the offset angle 850, η, i.e.,the arctangent of the projected offset distance, D, over the range, R.

Again, the offset angle may be invariant, and due to the decreasingmagnitude of the range, R, the distance D will likewise decrease. Forexample, a five meter offset distance at a range of 50 meters isapproximately 0.1 radians (using a small-angle approximation), which isan offset angle, η, of about 5.7 degrees. In some embodiments, theoffset angle may range from zero to ninety degrees from centerline, andin other embodiments the offset angle may range from five to forty-fivedegrees from a centerline or five to ten degrees from a centerline,i.e., off-axis. Some embodiments may have warheads that deploy aftward,where the offset angle may range from ninety degrees to one-hundredeighty degrees from a centerline, and other embodiments may range fromone-hundred thirty five degrees to one-hundred seventy five degrees froma centerline or one-hundred seventy degrees to one-hundred seventy-fivedegrees from a centerline. For that same offset angle, the offsetdistance at 100 meters to target is about ten meters.

FIG. 8E depicts, in a perspective of the paint ejector having an offsetangle bias from the forward-directed centerline of the air vehicle, thepaint ejector having a prior orientation, as in the banking maneuver atthe relative time, T₂, of FIG. 8A, that, in this example, would ejectpaint at relative time, T₄, in a direction missing the target by adistance, M. With a roll-to-point maneuver effected by relative time,T₄, the paint ejector is depicted as aligned to eject paint in adirection that is incident on the target. It is noted that while FIGS.6, 7, and 8A-8E depict, by example, a ground target, embodiments may beapplied to airborne targets as well.

FIG. 9 is an exemplary functional block diagram of the UAV processingand guidance and control subsystem 900 where the guidance sensor 910provides information about the external environment pertaining toseeking or tracking processing of a seeker or tracker processor 920. Aguidance sensor, and more generally, a guidance sensor suite, mayinclude a passive and/or active radar subsystem, an infrared detectionsubsystem, an infrared imaging subsytem, a visible light imagingsubsystem such as a video camera-based subsystem, an ultraviolet lightdetection subsystem, and combinations thereof. The seeker processor 920may include both image processing and target tracking processing, andtarget designation or re-designation input 921 that may be received froman uplink receiver 935 and/or as an output of a guidance processor 930.The image processing and/or target tracking information 922 may betransmitted via a downlink transmitter 923, which may be a part of anuplink/downlink transceiver. The guidance processor 930, in executinginstructions for guidance processing, may take in the target information924 from the seeker processor 920, and UAV flight status informationsuch as position, velocity, and/or attitude from the GPS receiver 931,and/or gyroscopes and accelerometers 932, if any. The guidance processor930, to receive navigation waypoints and/or target search optimizingtrajectories, may reference a memory store 933. For system embodiments,the guidance process 930 may receive and/or upload navigation waypointsand/or target search optimizing trajectories, by way of an external dataport 934, e.g., during a pre-launch phase, or by way of an uplinkreceiver 935, e.g., during a post-launch phase. The guidance processor930, as part of executing instructions for determining flight path, atrajectory, or a course steering angle and direction, may reference thewaypoint and/or surveillance optimizing trajectory information,particularly when not in a terminal homing mode. The guidance processor930 may receive a command via an uplink receiver 935 to switch orotherwise transition from a terminal homing mode to a target searchmode, i.e., non-terminal homing mode, and switch from a target searchmode to a terminal homing mode. The UAV may autonomously, or responsiveto an uplink, process images from a side-mounted camera, i.e. sensor 115(in FIG. 1), or other scene-sensing sensor, and switch to afront-mounted camera or other scene-sensing sensor. For example, avisual target lock by the seeker processor 930 may be tracked withreference to GPS coordinates and integrated into a terminal homingsolution that may be iteratively determined by the guidance processorexecuting instructions pertaining to determining a revisable terminalsolution. The guidance processor 930 may include a strap-down navigationsolution aided by the GPS receiver, and may accordingly support thestorage of pre-terminal commit points or return waypoints following abreak from terminal homing that may be initiated by an external uplinkor initiated autonomously based on scene changes during the terminalhoming phase. Thereafter, the UAV may return to a volume of spacewithin, proximate to, or substantially the same volume of space fromwhich it initiated the preceding terminal phase. Embodiments of theavionic sensors may include exemplary devices such as a digital camerahaving five megapixel resolution, an image rate of 60 Hz, digital zoom,e.g., 1×-3×, regional subframing, and automatic brightness control,and/or a long wavelength infrared camera having a 640×480 FPA format, aSTMicroelectronics of Geneva, Switzerland ARM™ 9 microcontroller, aSTMicroelectronics LIS3L02DQ MEMS 3-axis linear accelerometer, AnalogDevices, Inc. of Norwood, Mass. ADXRS612 gyroscopes, a SiliconMicrostructures, Inc. of Milpitas, Calif. SM5872 air speed sensor, a VTITechnologies, Inc. of China SCP1000-D01/D11 Pressure Sensor as Barometerand Altimeter, a Honeywell, Inc. of Plymouth, Minn. HMC 1043magnetometer, and a uBlox of Thalwil, Switzerland NEO-5Q GPS (L1, C/Acode) receiver and a patch L1 GPS antenna. Other GPS receivers andantennas may be used depending on the mission and expected environmentalconditions.

Embodiments of the UAV may exhibit flight air speed in the range of 57to 130 miles per hour (50-112 knots), however other air speeds arepossible. An example of a terminal homing mode may utilize a combinationof pursuit and proportional navigation guidance with a gravity bias thatmay be applied for strike sub-modes of the terminal homing mode, and anacceleration bias that may be applied for aerial intercept sub-modes ofthe terminal homing mode. The guidance processing 930 and autopilotprocessing 940 may execute instructions to effect a bank-to-turnguidance, for example in an elevon embodiment, to redirect the airvehicle by reorienting its velocity vector principally via roll angleand lift, and additional via propeller throttling. For example, one ormore control surfaces may be reoriented via one or more control surfaceactuators 950 causing forces and torques to reorient the air vehicle andthe portion of its linear acceleration that is orthogonal to itsvelocity vector. The portion of the linear acceleration of the airvehicle that is along the velocity vector is greatly affected byaerodynamic drag, and the linear acceleration may be increased via amotor processor 960 and a propeller motor 970. For embodiments with fullthree-axis control, additional control topologies may be implementedincluding skid-to-turn and other proportion-integral-differentialguidance and control architectures. The seeker processing, guidanceprocessing, motor processing, and/or autopilot processing may beexecuted by a single microprocessor having addressable memory and/or theprocessing may be distributed to two or more microprocessors indistributed communication, e.g., via a data bus.

FIG. 10 depicts an exemplary pitch channel autopilot of the UAV wherethe topology is an acceleration command, proportional-integral controlarchitecture in combination with an optional attitude command,proportional-integral control architecture. In the maneuver mode, M₁,the pitch channel generates elevator actuator command δ_(e) _(c) basedon a body acceleration command error, A_(ε), and the measured orestimated body pitch rate, ω_(y). In the optional pitch body-pointingmode, M₂, the pitch channel generates elevator actuator command δ_(e)_(c) based on a body attitude command error, θ_(ε), and the measured orestimated body pitch rate, ω_(y). The autopilot gains, K_(A), K_(Aε),K_(θ), and K_(q), may be fixed, adaptive or gain-scheduled, andoptionally some paths may not be used or mechanized. The integrator maybe a digital integrator, running a rate of 1/ΔT, e.g.,

$\frac{\Delta \; {Tz}}{z - 1},$

with numerical memory limits to avoid windup, where “z” isrepresentative of the z-transform of a delay, z⁻¹.

FIG. 11 depicts an exemplary roll channel autopilot of the UAV where thetopology is an attitude command, proportional-integral controlarchitecture. In the maneuver mode, M₁, the pitch channel generateselevator actuator command δ_(e) _(c) based on a body accelerationcommand error, A_(ε), and the measured or estimated body pitch rate,ω_(y). In the roll body-pointing mode, M₃, the roll channel generatesaileron actuator command δ_(a) _(c) based on a body attitude commanderror, φ_(ε), and the measured or estimated body roll rate, ω_(x). Theautopilot gains, K_(φ), and K_(p), may be fixed, adaptive orgain-scheduled, and optionally some paths may not be used or mechanized.The roll attitude command, φ_(c), may be generated during the maneuvermode, M₁, by applying an arctangent function to the estimated localvertical and horizontal inertial accelerations, i.e.,

Â_(z_(I_(c)))  and  Â_(y_(I_(c))).

The roll attitude command, φ_(c), may be provided during the rollbody-pointing mode, M₃, a roll angular command for angular targetalignment based on inertial instruments, estimates of the local level,and/or video processing the target image and the field of the targetimage. The target location may be estimated or provided by athird-party, post-launch, e.g., in local inertial coordinates or biasedGPS coordinates, and/or may be revised or established post-launch. Forexample, the target processing may estimate the relative location of thetarget in a pair of angles-of-arrival. The polar representation of theangles-of-arrival will have an angular component that may be treated asthe roll command for the autopilot when attempting to align the vehiclein roll for an offset warhead or paint ejector. See M₃ of FIG. 11, thatsupports the switch in alignment error 1110. The roll channel of FIG. 11also depicts a roll rate command limiter having a value of ±ω_(x(LIMIT))so that the air vehicle may not be commanded to spin faster than theangular rate sensors can measure. An air vehicle with an airspeed ofabout 120 mph and a roll rate of 150 degrees per second may be expectedto be able to orient the vehicle in the range of about 50 meters totarget. In some embodiments, the roll channel control or the rollchannel with the pitch channel control may be used to maintain theoffset angle correction via control surface actuation.

FIG. 12A is a flowchart 1200 depicting an exemplary flight processcomprising the steps of: (a) directing a UAV with an offset warheadtowards the target (block 1202); adjust UAV flight path for wind, orother error, correction (block 1203); sense offset error to target(block 1204); roll UAV to align windward (block 1205); and deploywarhead to target (block 1206).

FIG. 12B is a flowchart 1201 depicting a UAV in a nominal bank-to-turnflight control operation at time T₁; see FIG. 10, M₁ engaged (block1210). Also illustrated is a UAV engaged in an augmented bank-to-turncontrol operation at T₂; see FIG. 11 M₃ engaged (block 1220). Alsodepicted is a UAV disengaged from an augmented bank-to-turn controlflight operation at time T₃; see FIG. 11 M₃ disengaged (block 1230).Also illustrated is a UAV in an angled flight control operation forwarhead ejection/deployment at time T₄; see FIG. 10 M₂ engaged (block1240).

It is contemplated that various combinations and/or sub-combinations ofthe specific features and aspects of the above embodiments may be madeand still fall within the scope of the invention. Accordingly, it shouldbe understood that various features and aspects of the disclosedembodiments may be combined with or substituted for one another in orderto form varying modes of the disclosed invention. Further, it isintended that the scope of the present invention herein disclosed by wayof examples should not be limited by the particular disclosedembodiments described above.

1: A method of unmanned aerial vehicle (UAV) body re-orientationcomprising: determining, by a processor, a boresight offset angle errorcorrection value based on a distance between a target point and aboresight point of a body-fixed image frame; and effecting, by theprocessor, an onboard control surface actuation maneuver comprising anangular roll component to translate the target point in the body-fixedimage frame to thereby maintain an offset angle via the boresight offsetangle correction value. 2: The method of UAV body re-orientation ofclaim 1 further comprising: effecting, by the processor, an onboardcontrol surface actuation maneuver comprising a pitch component totranslate the target point in the body-fixed image frame to therebymaintain the offset angle via the boresight offset angle correctionvalue. 3: The method of UAV body re-orientation of claim 1 wherein theonboard control surface actuation maneuver further comprises orientingthe target point in the body-fixed image frame below a boresight pointin the body-fixed image frame. 4: The method of UAV body re-orientationof claim 1 wherein the onboard control surface actuation maneuverfurther comprises actuating one or more aileron actuators. 5: The methodof UAV body re-orientation of claim 1 wherein the onboard controlsurface actuation maneuver is by one of: a bank-to-turn guidance and askid-to-turn guidance. 6: The method of UAV body re-orientation of claim1 wherein the target point is based on a target in motion. 7: Anunmanned aerial vehicle (UAV) comprising: a processor having addressablememory, the processor configured to: determine a body roll angle errorbased on a target location in a body reference frame and an orientationof the UAV in the body reference frame; and effect a transition toreorient the UAV in attitude based on the determined body roll angleerror. 8: The UAV of claim 7 wherein the effected transition orients thetarget location in the body reference frame below the orientation of theUAV in the body reference frame. 9: The UAV of claim 7 wherein theeffected transition is further based on a range-to-target and via one ormore control surface commands.
 10. (canceled) 11: The UAV of claim 10wherein the one or more control surface commands are one or more aileronactuator commands. 12: The UAV of claim 7 wherein the effectedtransition is via at least one of: a bank-to-turn guidance and askid-to-turn guidance.
 13. (canceled) 14: The UAV of claim 7 furthercomprising a propeller, wherein the propeller is driven by at least oneof: a chemical battery store and a combustion engine. 15: The UAV ofclaim 7 wherein the target location is in motion and is an evasivetarget.
 16. (canceled)
 17. (canceled) 18: The UAV of claim 7 wherein theeffected transition is about a centerline of the UAV. 19: The UAV ofclaim 7 wherein the processor is further configured to: effect a payloadrelease, wherein the released payload contacts the target location. 20:The UAV of claim 7 wherein the body roll angle error is further based onat least one of: a GPS location of the UAV, a crosswind estimation, anda crosswind measurement. 21: The UAV of claim 7 wherein the targetlocation is determined by a guidance sensor suite. 22: The UAV of claim21 wherein the guidance sensor suite comprises at least one of: apassive radar subsystem, an active radar subsystem, an infrareddetection subsystem, an infrared imaging subsystem, a visible lightimaging subsystem, and an ultraviolet light detection subsystem. 23: TheUAV of claim 7 wherein the target location is received, by an antenna ofthe UAV, post-launch of the UAV by a third-party. 24: The UAV of claim 7wherein the target location is modified, by an antenna of the UAV,post-launch of the UAV by a third-party.